Dr Shams Hassan Faruqi sits amid his rocks and geological records, shakes his bearded head and stares at me. "I strongly doubt if the children are alive," he says. "Probably, they have expired." He says this in a strange way, mournful but resigned, yet somehow he seems oddly unmoved. As a witness, supposedly, to the mysterious 2008 re-appearance of Aafia Siddiqui – the "most wanted woman in the world", according to former US attorney general John Ashcroft – I guess this 73-year-old Pakistani geologist is used to the limelight. But the children, I ask him again. What happened to the children?